The file of this patent application includes duplicate copies of a compact disc with a file entitled xe2x80x9c108256 code.txtxe2x80x9d, created on Apr. 14, 2003, and having a size of 92,072 bytes (92,160 bytes on disc), which is hereby incorporated by reference.
The invention relates to signal processing, and more particularly relates to the processing of such signals to embed auxiliary data (e.g. identification or control data therein), and the subsequent extraction and use of such data.
The copying and redistribution of commercial imagery and video productions has long been a cause of lost revenues to the creators/producers of such material. The advance of technology has not only expanded the means of legitimate distribution for visual/video works, but has also made it easier to copy these materials for unauthorized purposes.
Various methods have been developed to eliminate or limit both sophisticated and unsophisticated illegitimate distribution. Some of these methods rely on physical means. Others employ a xe2x80x9cdon""t copyxe2x80x9d signal to disable a machine""s recording function.
In accordance with preferred embodiments of the invention, a multi-bit control message (sometimes termed a xe2x80x9cdigital watermarkxe2x80x9d) is embedded directly into an audio signal. Hardware or software systems can then read this control message and, for example, disable recording functions if so instructed.